# -*- coding: UTF-8 -*-
#python tkinter menu
#python version 3.3.2
#EN = Window 7


from Tkinter import *
import random
import threading
import time
import sys
 
#画布大小
WIDTH = 400
HEIGHT = 300
SIGMA = 10
BUZZ = 2
RADIUS = 2
LAMBDA = 10
FILL = 'red'

stop = 0                                # Set when main loop exits
 
def particle(canvas):
     r = RADIUS
     x = random.gauss(WIDTH/2.0, SIGMA)
     y = random.gauss(HEIGHT/2.0, SIGMA)
     p = canvas.create_oval(x-r, y-r, x+r, y+r, fill=FILL)
     while not stop:
         dx = random.gauss(0, BUZZ)
         dy = random.gauss(0, BUZZ)
         dt = random.expovariate(LAMBDA)
         try:
             canvas.move(p, dx, dy)
         except TclError:
             break
         time.sleep(dt)
 
def main():
     global stop
     root = Tk()
     canvas = Canvas(root, width=WIDTH, height=HEIGHT)
     canvas.pack(fill='both', expand=1)
     #粒子数目
     np = 30
     if sys.argv[1:]:
         np = int(sys.argv[1])
     for i in range(np):
         t = threading.Thread(target=particle, args=(canvas,))
         t.start()
     try:
         root.mainloop()
     finally:
         stop = 1
 
main()